Index Register - Mitsubishi Electric MELSEC Q Series Handbook

7
REPLACEMENT OF PROGRAM

7.7.7 Index register

(1) Replacing index register
"Z, Z1 to Z6, V, V1 to V6" and "Z0 to Z15" are used as index register for the AnS series and Q series,
respectively. Therefore, their specifications differ.
"V" is used as edge relay for the Q series. The device is used to memorize the PLS/PLF information to
contacts from the start of the ladder block.
The following table shows replacement of index register when AnS series program was utilized to the Q
series with "Change PLC type".
AnS series
Z
Z1 to Z6
V
V1 to V6
Point
When modifying contact instructions of timer/counter with indexes, AnA/AnUCPU has no restrictions on
index registers.
For QCPU, only "Z0, Z1" can be specified for index registers when modifying contact instructions of
timer/counter with indexes according to its specifications.
When using index registers other than "Z0, Z1" in the existing AnA/AnUCPU, it is replaced with
"SM1255" as unconvertible instruction. Therefore, correcting/changing program is required.
Q series
Z0
Z1 to Z6
Z7
Z8 to Z13
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